The data transport network is currently developing toward the direction of more and more nodes and more and more complex topology, the mesh network has become the ultimate goal of the development of optical transport network (OTN), packet transmission network (PTN), Synchronous Digital Hierarchy (SDH) network, and so on. In a mesh network, currently linear protection such as 1+1 and 1:1 as well as ring shared protection can be deployed; but these methods are unable to make full use of the reserved bandwidth resource of the mesh network, resulting in low overall network utilization.
Intra-network shared protection is a new universal protection method, its most important feature is to achieve that the protected services share the protection resources in the mesh network, thereby enhancing the overall network utilization. Since a plurality of protected services share the same segment of protection resources, when a plurality of protected services need to use the protection resources, there emerges competition for the resources, and preemption is one of the simplest mechanisms to solve the competition. Usually, people set service levels for the protected services to serve as a basis of judgment on preemption.
In the field of protection technology, there is also the priority principle between the manual command and the link state. Usually there are several levels of manual commands, for example, there are force switching command and manual switching command in the linear protection, wherein the force switching command has a higher priority than the link failure, while the manual switching command has a lower priority than the link failure.
Due to the existences of service levels and manual command priorities, it needs to judge these two dimensions in the shared protection in the mesh network, moreover, it needs to determine which dimension is taken as the reference, for example, for a high-level command for a service with low priority and a low-level command for a service with high priority, it is difficult to determine which one takes precedence, thereby resulting in the need to develop a set of very complex rules in order to meet the requirements.